This invention relates to hand brake mechanisms adapted for use on railway cars. More particularly, the invention relates to mechanisms of the quick-release type having locking structures preventing accidental brake release.
My U.S. Pat. Nos. 3,425,294 and 3,988,944 disclose hand brake mechanisms of the quick-release type, which are adapted for use on railway cars. The disclosed mechanisms also incorporate structure providing for gradual release of the car brakes. Both gradual and quick release are effected without spinning of the handwheel which is manually rotated for application and for gradual release of the brakes. More particularly, two clutches are arranged in series relationship in a power train from the handwheel to the car brakes. A self-energizing friction clutch associated with coaxial separate shafts in the power train provides for gradual release of the brakes. A manually-operated clutch of the jaw type provides for quick release of the brakes. The mechanism of the patents includes a pivoted yoke assembly having shift lever or fork components, and a cam shaft having a handle or lever connected thereto for manual operation. The cam shaft is provided with a cam operating in one direction of rotation of the shaft to pivotally move the yoke assembly so as to separate components of the quick-release clutch for releasing the brakes. A second cam on the cam shaft functions upon rotation of the cam shaft in the opposite direction to cam the yoke assembly in a direction to drivingly engage the clutch components, and to assist a biasing spring in maintaining the engagement of the components.
U.S. Pat. No. 3,040,597 discloses a non-spin hand brake mechanism having gradual-release and quick-release clutch structures arranged in series in a power train from a handwheel to the car brakes. The mechanism includes a trip bar means or yoke assembly for operation of the quick-release clutch, and a trip cam means engaging and pivotally moving the trip bar means. The trip cam means includes a cam arm on a cam shaft, and the cam arm engages the trip bar means for disengaging components of the quick-release clutch. A safety arm also is provided on the cam shaft, and it overlies one component of the quick-release clutch when its components are in driving engagement, to prevent the one component from moving out of such engagement.